


Frenzied

by daemonhart



Category: Undertale (Video Game)
Genre: Alternate Universe, Anal Sex, Feral Behavior, Interspecies, Knotting, M/M, Mating Cycles/In Heat, Plot What Plot/Porn Without Plot, Roleplay
Language: English
Status: Completed
Published: 2018-02-12
Updated: 2018-02-12
Packaged: 2019-03-17 06:33:52
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 703
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13653435
Author URL: https://archiveofourown.org/users/daemonhart/pseuds/daemonhart
Summary: [Drabble] Humans make great prey, especially when they're willing.





	Frenzied

**Author's Note:**

  * Inspired by [2nd place prize of my giveaway!!!](https://archiveofourown.org/external_works/356982) by Kierie. 



> This drabble is based on a version of Sans that I use to roleplay. He is very much the same as canon, except during heats or in moments of great distress, his magic goes haywire and he becomes a more feral monster. Neither form remembers much about the other, aside from reflexive responses. The OC involved is my partner's, Tokala, a Third Human (Bravery). I won a lovely artwork of them from Kierie, then decided to write about it.

“Agh, S-Sans! Too rough!” Tokala panted. The cheeks of his ass ached from being beaten over and over by the monster’s pelvis with every thrust. The beastly skeleton didn’t seem interested in obeying. He growled down at his partner, feeling the base of his cock starting to swell. The human didn’t notice right away; the relentless pounding left his hole able to take the gradual increase without trouble. Sans’ hips shifted for a better angle so he could be sure he could push deep enough to tie. “Oh! Oh, there!” Tokala pleaded, whipping his head back against the pillow. “Yesss! Unh~ Please…!” He couldn’t make up his mind over whether it was too much or not enough. His thoughts were too clouded to even make heads or tails of if he was in pain from being fucked raw. The monster’s magic was just as intoxicating as ever.

Sans ran his tongue across his jagged teeth. A willing mate was a real treat for his feral mind. The way the human’s muscle tightened around his shaft when he withdrew, then accepted it so readily with the next thrust only encouraged the knot to swell. Every signal told him his bitch was ready to be tied and filled - his crescendoing cries, his eager ass, his arching body. Soon, Tokala could feel the thickening bulb’s resistance every time it forced inside. His eyes squeezed shut.  _Yes_. This was the best part of getting fucked by this wild animal shaped like his partner. The violence and bare lust were a rush, but the way Sans’ cock forced the muscle wider and wider to accommodate its girth was just  _indescribable_. He couldn’t stop the monster even if he wanted to, but relinquishing power to a creature acting on base instincts was liberating. All he had to do was enjoy every moment of it and he’d be rewarded with more. “It’s getting so  _big_ , Sans~ Mmmf, good monster! Good – ooh~ Haahh, so thick!” He still wasn’t sure Sans could understand words like this or if he was just reacting to the sound, but it always drew an enthusiastic reaction. Harder thrusts, a starving expression. Pre dribbled from Tokala’s dick onto his belly, milked by his partner’s unrelenting thrusts.

The sensation of the human’s muscle straining and stretching around the sensitive, swelling flesh became too much for Sans to handle. He pushed his hands under Tokala’s legs and shoved them into the air, rising to his haunches and doubling his partner over. His tail swept behind him to keep him balanced. Another hard push and the knot sank inside. The skeleton wasn’t quite done, though. His hips continued to piston his cock against the deep warmth, striking the other’s prostate over and over and over while working up to a complete tie. Tokala moaned out incoherently and crossed his arms back around the pillow just to hold on to  _something_. His eyes rolled back and his jaw hung open. So full! He couldn’t handle anymore! Tension swept through his muscles and his dick throbbed, shooting a milky-white thread against his own stomach. Each further thrust forced every drop he had to give until he’d run dry.

The bulb swelled until it was a struggle even to move, especially with Tokala’s muscles clenching around it. Sans did what little else he could to seat it deep inside, then hissed through his teeth once orgasm struck him, too. Unlike the human, he had  _much_ to give. Minute after minute passed, his cock pumping its heavy load into the breeder beneath him. Tokala’s eyes closed in exhaustion. The feeling of pressure continued to build inside, leaving his stomach perhaps slightly rounder than it was before. “Mnf…hah…” he exhaled. Once Sans was done ten or so minutes later, he tugged the shrinking knot free and glanced down to enjoy his handiwork. Tokala’s hole quivered, still agape and leaking the glowing fluid. It was enough to make the human wince tiredly and writhe, but he was still too exhausted to untangle his arms from the pillow.

Sans took in his worn, flushed expression with satisfaction. He couldn’t remember what he’d done to earn such a good mate, but he was definitely glad he did.


End file.
